Adhesive bonding is a common way of fabricating various kinds of components, such as aircraft components. When bonding parts of a component together, a specific amount of adhesive is used to ensure proper bonding of the component. The specific amount of adhesive is typically quantified as the thickness of the layer of adhesive.
However, adhesive application between bonded surfaces of a component can be an inexact process. The process typically includes dispensing an approximate amount of the adhesive to the bonded surface. The adhesive is then spread and leveled on the bonded surface to form an intermediate layer of adhesive having a required and/or desired thickness. A straight edge (e.g., a flat-edged trowel) or a notched trowel (e.g., a plurality of square or triangular teeth disposed on a working edge) may be used to spread and level the adhesive on the bonded surface.
Unfortunately, use of a straight edge to level the adhesive may provide an inexact and/or inconsistent thickness of the intermediate layer. Further, use of a notched trowel may be sensitive to the angle of the notched trowel with respect to the bonded surface to which the adhesive is applied (e.g., as the angle of the notched trowel with respect to the bonded surface changes, the thickness of the intermediate layer of adhesive may also change). For example, using a conventional notched trowel disposed at a 90° angle with respect to the surface to which the adhesive is applied may yield an intermediate layer having a first thickness. Using the same notched trowel disposed at a 45° angle with respect to the surface to which the adhesive is applied may yield a second thickness. The second thickness may be considerably less than the first thickness (e.g., approximately 70% of the first thickness). Given the human element of the spreading and leveling process, the overall thickness of the intermediate layer of adhesive may vary across the bonded surface.
Thus, the use of a straight edge or a notched trowel may lead to too little adhesive or too much adhesive being applied to the bonded surface. Too little adhesive may lead to an insufficient bond between bonded surfaces of the component. Too much adhesive may squeeze out from between bonded surfaces of the component and/or may form a bond line that is too thick. To avoid applying too little adhesive, operators may use too much adhesive and remove (e.g., clean up) any excess adhesive that may squeeze out. This excess adhesive removal process may take longer than the application process and requires that excess adhesive be properly disposed of due to hazardous chemicals in the adhesive compound. To avoid having to clean up excess adhesive, operators may use too little adhesive, which may cause improper bonding and possible failure of the component.
Accordingly, those skilled in the art continue with research and development efforts in the field of application of a curable material to a surface.